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BackgroundDown syndrome (DS) is the most common syndromic immunodeficiency with an increased risk of infection, mortality from sepsis, and autoinflammation. Innate immune function is altered in DS and therefore we examined responses in CD11b and Toll like receptor 4 (TLR-4), which are important immune cell surface markers upregulated in response to Lipopolysaccharide (LPS) endotoxin, and the immunomodulator melatonin. Neutrophil and monocyte responses to LPS and melatonin in children with Down syndrome (DS) who were clinically stable were compared to age-matched controls. Whole blood was incubated with LPS and melatonin and the relative expression of CD11b and TLR-4 evaluated by flow cytometry.ResultsChildren with DS had an increased response to LPS in neutrophils and intermediate monocytes, while also having elevated TLR-4 expression on non-classical monocytes compared to controls at baseline. Melatonin reduced CD11b expression on neutrophils, total monocytes, both classical and intermediate sub-types, in children with DS and controls.ConclusionMelatonin could represent a useful clinical adjunct in the treatment of sepsis as an immunomodulator. Children with DS had increased LPS responses which may contribute to the more adverse outcomes seen in sepsis.

Immunotherapy has become an important ally in the fight against distinct types of cancer. However, the metabolic plasticity of the tumor environment frequently influences the efficacy of therapeutic procedures, including those based on immunological tools. In this scenario, immunometabolic adjuvants arise as an alternative toward the development of more efficient cancer therapies. Here we demonstrated that the combination of melatonin, a neuroimmunomodulator molecule, and an indoleamine 2,3-dioxygenase (IDO) inhibitor (1-methyl-DL-tryptophan, DL-1MT) improves the efficacy of an immunotherapy (gDE7) targeting human papillomavirus (HPV)-associated tumors. Melatonin or IDO inhibitors (D-1MT and DL-1MT) directly reduced proliferation, migration, adhesion and viability of a tumor cell line (TC-1), capable to express the HPV-16 E6 and E7 oncoproteins, but could not confer in vivo antitumor protection effects. Nonetheless, combination of gDE7 with melatonin or D-1MT or DL-1MT enhanced the antitumor protective immunity of gDE7-based vaccine in mice. Notably, expression of IDO1 in stromal cells and/or immune cells, but not in tumor cells, inhibited the antitumor effects of the gDE7, as demonstrated in IDO1-deficient mice. Finally, co-administration of gDE7, melatonin and DL-1MT further improved the protective antitumor effects and the numbers of circulating E7-specific CD8+ T cells in mice previously transplanted with TC-1 cells. The unprecedented combination of melatonin and IDO inhibitors, as immunometabolic adjuvants, thus, represents a new and promising alternative for improving the efficacy of immunotherapeutic treatments of HPV-associated tumors.

Cervical cancer is a major public health problem and one of the leading causes of cancer deaths in women. Virtually all cases of cervical cancer, as well as a growing share of anal and head/neck tumors, are associated with human papillomavirus (HPV) infection. Despite the effectiveness, the available prophylactic vaccines do not benefit women with cervical lesions or cancer. Therefore, the search of new immunotherapeutic approaches to treat HPV-induced tumors is still a priority. The present study characterizes a therapeutic antitumor vaccine based on the genetic fusion of the Herpes simplex virus-1 (HSV-1) glycoprotein D (gD) with the E7 oncoprotein from HPV-16 (gDE7). Two subcutaneous doses of gDE7, admixed with poly (I:C), conferred complete and long-lasting therapeutic antitumor protection on mice previously challenged with tumor cells expressing the HPV-16 oncoproteins. The vaccine induced multifunctional E7-specific CD8 T cells with cytotoxic activity and effector memory phenotype (CD44 CD62L). In addition, gDE7 admixed with poly (I:C) vaccination controlled the expansion of tumor-induced regulatory T cells and myeloid-derived suppressor cells. More importantly, gDE7 activated mouse CD11c CD8α and human BDCA3 dendritic cells (DC), specialized in antigen cross-presentation to CD8 T cells, under conditions. These results indicated that the activation of a specific DC population, mediated by gD, improved the antigen-specific immune responses and the therapeutic performance induced by antitumor vaccines. These results open perspectives for the clinical testing of gDE7-based vaccines under the concept of active immunization as a tool for the therapeutic control of cancer..

In this report, we analyzed the prevalence of the sat gene in 336 Escherichia coli samples collected from stools of children with and without diarrhea in Brazil and in 100 uropathogenic E. coli strains. The results show a high correlation between diffusely adhering E. coli (DAEC) and the presence of sat (44%) in intestinal isolates. DAEC strain FBC114 expresses a 107-kDa protein, which showed 98% homology with Sat.

Indoleamine 2,3-dioxygenase 1 (IDO1), the rate-limiting enzyme of tryptophan catabolism, has been strongly associated with the progression of malignancy and poor survival in melanoma patients. As a result, IDO1 is a leading target for interventions aimed at restoring melanoma immune surveillance. Here, in a scenario involving the tryptophan catabolism, we report that melatonin biosynthesis is driven by 1-methyl-tryptophan (1-MT), a competitive inhibitor of IDO1, in human fibroblasts, melanocytes and melanoma cells. In addition to melatonin biosynthesis, 1-MT induced the expression of tryptophan hydroxylase, arylalkylamine-N-acetyltransferase and hydroxyindole O-methyltransferase mRNA in fibroblasts and melanocytes. We observed a great variability in the levels of IDO1 mRNA expression and kynurenine release between skin cells and melanoma cell lines in response to interferon-c, a classical IDO1 inducer. In this setting, melatonin was shown to downregulate kynurenine production. Furthermore, in a condition of low basal activity of IDO1, it was observed that 1-MT, as well melatonin, inhibited the proliferation of human melanoma cells. Taken together, our results suggest that 1-MT may serve as more than just a tool to disrupt tumor immune escape (via the inhibition of IDO1) because it was shown to act directly on the proliferation of human melanoma cells and induce melatonin biosynthesis in the tumor milieu. Moreover, 1-MT-mediated inhibition of IDO occurs in normal skin and melanoma cells, which addresses the possibility that all cells in the skin microenvironment can be targeted by 1-MT. Our findings provide innovative approaches into understanding tumor therapy related to the control of tryptophan metabolism by 1-MT.

PRUPOSE Bacterial translocation has been shown to occur in critically ill patients after extensive trauma, shock, sepsis, or thermal injury. The present study investigates mesenteric microcirculatory dysfunctions, the bacterial translocation phenomenon, and hemodynamic/metabolic disturbances in a rat model of intestinal obstruction and ischemia.METHODSAnesthetized (pentobarbital 50 mg/kg, i.p.) male Wistar rats (250–350 g) were submitted to intestinal obstruction or laparotomy without intestinal obstruction (Sham) and were evaluated 24 hours later. Bacterial translocation was assessed by bacterial culture of the mesenteric lymph nodes (MLN), liver, spleen, and blood. Leukocyte-endothelial interactions in the mesenteric microcirculation were assessed by intravital microscopy, and P-selectin and intercellular adhesion molecule (ICAM)-1 expressions were quantified by immunohistochemistry. Hematocrit, blood gases, lactate, glucose, white blood cells, serum urea, creatinine, bilirubin, and hepatic enzymes were measured.RESULTSAbout 86% of intestinal obstruction rats presented positive cultures for E. coli in samples of the mesenteric lymph nodes, liver, and spleen, and 57% had positive hemocultures. In comparison to the Sham rats, intestinal obstruction induced neutrophilia and increased the number of rolling (~2-fold), adherent (~5-fold), and migrated leukocytes (~11-fold); this increase was accompanied by an increased expression of P-selectin (~2-fold) and intercellular adhesion molecule-1 (~2-fold) in the mesenteric microcirculation. Intestinal obstruction rats exhibited decreased PaCO2, alkalosis, hyperlactatemia, and hyperglycemia, and increased blood potassium, hepatic enzyme activity, serum urea, creatinine, and bilirubin. A high mortality rate was observed after intestinal obstruction (83% at 72 h vs. 0% in Sham rats).CONCLUSIONIntestinal obstruction and ischemia in rats is a relevant model for the in vivo study of mesenteric microcirculatory dysfunction and the occurrence of bacterial translocation. This model parallels the events implicated in multiple organ dysfunction (MOD) and death.